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z32 afm with 450cc injectors and a couple of problems..

Posted: Wed Aug 01, 2007 10:27 am
by Chris86NA2T
ive been running these injectors and afm with a romlator forever, with reasonable results.. i finally installed nistune and i can get the car to pretty much run the same as it did by using the same K, Null, load scales and fuel/timing maps as the bin file i made with the romulator..

today i tried to start fresh with the stock bin file and adjust for the injectors and afm from there.. i resized the injectors and it took me from a 607k to a 350k which seems pretty reasonable. when i changed my afm setting to a z32 meter it recalculated the K to be 1013 which is pretty rediculous... any ideas here?


when i use my original romulator setting the car does run pretty close to what it did before, but the increased functionality of nistune has revealed some problems.. i

have a k value of 285 and a null of 80 which has worked pretty well.. the problem i have is at idle. AFRs under load are reasonable and controlable. at idle i am so lean that the car barely runs. its well into the 18s... change the null has absolutly no effect on the afr or how the car idles. if i change the actual cell in the fuel map its very inconsistant. if i try to richen it by even half a point or so it will change from 18 afrs to the 10s.

and lastly.... my load scales are recalculated for the 285k that i have been using. the range is from 7 to about 60 for the fuel and timing. under low boost in second gear the car immediatly moved to the last load scales and stayed there while under power. im sure it should have much more range than that.. what am i missing here?

any advise would be greatly appreciated. thanks

Re: z32 afm with 450cc injectors and a couple of problems..

Posted: Wed Aug 01, 2007 11:20 pm
by Hendrick301
Chris86NA2T wrote:ive been running these injectors and afm with a romlator forever, with reasonable results.. i finally installed nistune and i can get the car to pretty much run the same as it did by using the same K, Null, load scales and fuel/timing maps as the bin file i made with the romulator..

today i tried to start fresh with the stock bin file and adjust for the injectors and afm from there.. i resized the injectors and it took me from a 607k to a 350k which seems pretty reasonable. when i changed my afm setting to a z32 meter it recalculated the K to be 1013 which is pretty rediculous... any ideas here?


when i use my original romulator setting the car does run pretty close to what it did before, but the increased functionality of nistune has revealed some problems.. i

have a k value of 285 and a null of 80 which has worked pretty well.. the problem i have is at idle. AFRs under load are reasonable and controlable. at idle i am so lean that the car barely runs. its well into the 18s... change the null has absolutly no effect on the afr or how the car idles. if i change the actual cell in the fuel map its very inconsistant. if i try to richen it by even half a point or so it will change from 18 afrs to the 10s.

and lastly.... my load scales are recalculated for the 285k that i have been using. the range is from 7 to about 60 for the fuel and timing. under low boost in second gear the car immediatly moved to the last load scales and stayed there while under power. im sure it should have much more range than that.. what am i missing here?

any advise would be greatly appreciated. thanks

I am running the 420cc injectors on my z31 turbo as well, my kconst is at 376 and latency at 79.

i have the stock afmthis is not perfect, as the car runs fine at idle once its warmed up, but first starts and cold starts have a loopy idle after about 1 min, or once the temp value is at 50. once it reads 80 everything runs well (warmed up)


fuel load is at starts at 10 and up to 79, the min pulsewith is at 6 to 4

Re: z32 afm with 450cc injectors and a couple of problems..

Posted: Thu Aug 02, 2007 5:39 am
by Bernardd
Chris86NA2T wrote:ive been running these injectors and afm with a romlator forever, with reasonable results.. i finally installed nistune and i can get the car to pretty much run the same as it did by using the same K, Null, load scales and fuel/timing maps as the bin file i made with the romulator..

today i tried to start fresh with the stock bin file and adjust for the injectors and afm from there.. i resized the injectors and it took me from a 607k to a 350k which seems pretty reasonable. when i changed my afm setting to a z32 meter it recalculated the K to be 1013 which is pretty rediculous... any ideas here?

I tried to resize for injectors and maf on my version of nistune and it gave me a weird result as well. Try loading a new version and compare to a hand calc'd result. I have a 012F kvalue and a 5A null value for 440's/z32maf


when i use my original romulator setting the car does run pretty close to what it did before, but the increased functionality of nistune has revealed some problems.. i

have a k value of 285 and a null of 80 which has worked pretty well.. the problem i have is at idle. AFRs under load are reasonable and controlable. at idle i am so lean that the car barely runs. its well into the 18s... change the null has absolutly no effect on the afr or how the car idles. if i change the actual cell in the fuel map its very inconsistant. if i try to richen it by even half a point or so it will change from 18 afrs to the 10s.

do your commanded afr's match the wideband readings in most cells? if not your k and latency are too far out. are you expecting the changes to happen instantly? if the tuning changes are happening at a delayed rate, i would either restart nistune or do an upload. the romulator is a weird beast at the best of times.

and lastly.... my load scales are recalculated for the 285k that i have been using. the range is from 7 to about 60 for the fuel and timing. under low boost in second gear the car immediatly moved to the last load scales and stayed there while under power. im sure it should have much more range than that.. what am i missing here?

what is the calc'd tpscale in the datalog? change it to whatever the max scale calc'd is and you're good to go. post the datalog/binfile if possible

any advise would be greatly appreciated. thanks

Posted: Fri Aug 17, 2007 5:43 pm
by Matt
I've added an investigate item for the K value to double check against hand calc since you guys are noticing a problem with it

Posted: Tue Aug 21, 2007 12:48 am
by Matt
Okay this is really strange... and I did notice this also on RB30 when trying to use RB25 AFM on my R31

CA18 190HP to Z32 550HP K * 2.89
R32 300HP to Z32 550HP K * 1.83
SR20 290HP to Z32 550HP K * 1.89

.... now

Z31 ??? HP to Z32 550HP K * 0.8463
The K is based from what bernard posted for his upgrade
(HP works out to be 649HP for Z31 MAF)....

that isn't right. usually the multiplier makes the K bigger but for our cars it is actually smaller. this could be because of the AFM offset being modified in the ECU hardware perhaps.... in that case there would be a hard coded multiplier offset for our ECUs perhaps?

currently i assume 190HP for Z31. lets just say it is really 250HP which may be more realistic (i have no flow number for our MAFs)
250HP to 550HP = 550/250 = 2.2 multiplier - 1.4 multiplier offset = 0.8463

I dont know if this is the real life number but could be close.... i need to find the real Z31 MAF HP number to confirm this.

Posted: Tue Aug 21, 2007 10:38 am
by Bernardd
My 3150 lb car reached 107 in the 1/4 with a maf reading of 5.9 or so. I would say it's worth a lot more than most give credit.

Posted: Tue Aug 21, 2007 12:18 pm
by Matt
The Z31 VG30 would probably also have a higher HP reading than the R31 RB30 .... it has a larger diameter ... but that is not always a guarantee (given Q45 is larger diameter than Z32 but will top out sooner)

PL has indicated that he might be able to flow test some of these for us....